JPH02255827A - Cure accelerator for epoxy resin, curing agent composition containing same and epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain the title cure accelerator excellent in compatibility with an acid anhydride curing agent, an epoxy resin or the like and storage stability and capable of giving a colorless, transparent and uniform cured product by modifying a zinc organic carboxylate by mixing under heating with an acid anhydride and a phenol. CONSTITUTION:A zinc organic carboxylate of formula I (wherein R1 and R2 are each a phenyl, a nucleus-substituted phenyl having a 1-10C alkyl, a naphthenic acid residue, a linear or branched alkyl or alkenyl or a linear or branched hydroxy 1-21C alkyl or alkenyl) is modified by mixing under heating with at least one acid anhydride (e.g. phthalic anhydride) and at least one phenol of formula II (wherein R3 is H, CH3 or a 1-16C linear or branched alkyl; and R4 is H, OH, a methyl, a methoxy, an ethoxy, a methoxyethyl, a methoxycarbonyl or a methoxycarbonylmethyl) to obtain a cure accelerator for epoxy resin comprising a modified zinc carboxylate.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an organic carboxylic acid zinc curing accelerator having excellent solubility with acid anhydride curing agents and epoxy resins, and further relates to the curing accelerator. An acid anhydride curing agent composition for epoxy resin, which is suitable for optical applications such as optical materials such as optical lenses, prisms, and transparent flat plates, light emitting elements such as light emitting diode encapsulants, and optical disk substrates; The present invention relates to an epoxy resin composition.

(Prior Art) Epoxy resins have excellent mechanical, electrical, thermal, and chemical properties, and are therefore used in a wide variety of applications, such as casting materials and sealing materials. As for how to use epoxy resin, the liquid type is superior in terms of workability, but the liquid type, in which a curing agent such as an acid anhydride and a curing accelerator are blended with the epoxy resin, has a short shelf life. Generally, the base material is made of epoxy resin etc.
1).

A two-component formulation is used in which a curing agent (n) consisting of an acid anhydride, a curing accelerator, etc. is separated, and (1) and (II) are mixed during curing.

In recent years, cured epoxy resins cured with acid anhydride curing agents have come to be used for optical applications such as optical lenses, prisms, light emitting diodes, and optical disk substrates.

Since cured epoxy resin products for such optical applications are strongly required to be colorless and transparent, strict performance requirements are also imposed on the curing accelerators used for these applications.

As acid anhydride curing accelerators, ■ tertiary amines or imidazoles, etc. and/or their organic carboxylates, ■ tertiary amines, imidazoles, etc. and/or their organic carboxylates. A combination system with metal salts of organic carboxylic acids such as zinc organic carboxylates is commonly used, but the cured product is not transparent due to the presence of tertiary amines, etc. However, it is colored and is not suitable for optical purposes.

(Problems to be Solved by the Present Invention) It is already known that a cured epoxy resin using organic zinc carboxylate as a curing accelerator is colorless and transparent (27th National SAMPE Sym
posium, MAY, 4-6.1982). However, organic zinc carboxylates have the disadvantage of poor solubility in acid anhydrides and epoxy resins, which are hardeners. The curing agent composition mixed with this acid anhydride does not become a uniform liquid,
Phase separation of organic zinc carboxylate and resulting cloudiness occur. Furthermore, in epoxy resin compositions in which zinc organic carboxylate is blended with epoxy resin and acid anhydride,
Since organic zinc carboxylate has poor solubility in epoxy resins and acid anhydrides, there have been problems such as uneven curing and poor workability.

In preliminary studies conducted by the present researchers, cured epoxy resins using organic zinc carboxylates are colorless and transparent, especially at 12
Although it has been confirmed that it has excellent colorless transparency even under high-temperature, rapid-curing conditions at temperatures above 0°C, it may also have poor solubility in acid anhydrides or epoxy resins and uneven curing. I admit it.

Therefore, it is practically difficult to use organic carboxylic acid substituent alone as a curing accelerator, and it is necessary to use tertiary amines, imidazoles, etc., or to combine these with a small amount of organic carboxylic acid zinc17, organic The reality is that zinc carboxylate dissolves in acid anhydrides, epoxy resins, etc., and is used only in small amounts.

In view of these problems, the inventors of the present invention
Preferably, even in fast-curing dyeing at 130°C or higher, a colorless and transparent uniform cured product can be obtained, and an acid anhydride-based curing agent and/or
In order to develop a curing accelerator that has excellent solubility in epoxy resin compositions and excellent storage stability, the present invention has been completed after conducting intensive studies.

(Means for Solving the Problems) The present inventors have used one or more acid anhydrides and the following (B).
If organic zinc carboxylate is heat-denatured under certain conditions in the presence of one or more phenols represented by the general formula, epoxy resin or We have discovered scales that are easily soluble in acid anhydrides and the like.

carbonyl group, methoxycarbonylmethyl group) The ratio of the phenols represented by formula (B) used for modifying organic carboxylic acid zinc and organic carbon M zinc (hereinafter referred to as phenol zinc ratio) is expressed by formula (C). The ratio is 2 to 9, preferably 3 to 7. When it is 2 or less, the phenol zinc ratio of organic carboxylic zinc -Y/X...
(C) (X is the number of moles of zinc organic carboxylate, Y is the value obtained by multiplying the number of moles of phenols by the number of hydroxyl groups in the phenols.) (R, is a hydrogen atom or a methyl group, cl to c1 A linear or branched alkyl group, R4 is a hydrogen atom or a hydroxyl group, a methyl group, a methoxy group, an ethoxy group, a methoxyethyl group,
Poor solubility in methoxy acid anhydride and epoxy resin,
If it is 9 or more, the solubility is good, but the cured epoxy resin has various properties other than transparency, such as glass transition temperature,
Moisture resistance etc. deteriorate, making it difficult to use in practice.

In addition, the ratio of the acid anhydride used for modifying the organic zinc carboxylate and the organic zinc carboxylate is as follows.

(referred to as acid anhydride zinc ratio) is represented by formula (D) and ranges from 2 to 9, preferably from 3 to 7.

Zinc acid anhydride ratio - Z / When the ratio is less than 2, the solubility of the organic zinc carboxylate is poor and it becomes difficult to use it in practice.On the other hand, when the ratio is more than 9, the acid anhydride remains unreacted.

However, when producing the acid anhydride-based pre-curing composition in one step as described below, the acid anhydride zinc ratio is 9 or more.

As the organic zinc carboxylic acid used in the present invention, those exemplified by the following general formula (A) are effective (Rl, R2 are the same or different, and are a phenyl group, a nucleus having a C1 to C1° alkyl group). Substituted phenyl group, naphthenic acid residue, CI
- C21 linear or branched alkyl group or alkenyl group, linear or branched C1 to C□ alkyl group or alkenyl group having a hydroxyl group) Specifically, W# zinc acid, zinc hexanoate, 2 - Zinc ethylhexanoate, zinc laurate, zinc balmitate, zinc stearate, zinc ricinoleate, zinc benzoate, monocyclic, bicyclic, bicyclic naphthenic acid residues having 6 to 20 carbon atoms, etc. . These can be used alone or in combination of two or more.

As the phenols used in the present invention, one or more phenols corresponding to formula (B) -E are used. Specifically, phenol, p-cresol or m-cresol, 0-cresol, p-ethylphenol, m-
Ethylphenol, 0-ethylphenol, p-isobrobylphenol, m-isopropylphenol, O-
Isopropylphenol, p-tert-butylphenol, p-butylphenol, m-butylphenol,
0-butylphenol, p-octylphenol, p-
Alkylphenols such as laurylphenol, p-
Alkoxyphenols such as methoxyphenol, m-methoxyfuta, nor2guaiacol, p-ethoxyphenol, and guetol, p-methoxyethylphenol, hydroquinone, p-methyl oxybenzoate, p
-Hydroxyphenylacetic acid methyl ester, etc.

The acid anhydride used in the present invention is one or more types of polybasic acid carboxylic acid anhydrides, specifically phthalic anhydride, tetrahydrophthalic anhydride, hexanedolphthalic anhydride,
Methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, J-isopropyl-4-methyl-bicyclo[2,2,1octan-5-ene-2,3-dicarboxylic anhydride and its hydride, anhydride 3 .6-endomethy1/ntetrahydrophthalic acid, maleated allocimene and its hydride, maleated myrcene and its hydride, methylnazic! ! ! Anhydrides and their hydrides, biromelli l-acid anhydride, dodecenylsuccinic anhydride and its hydrides, anhydrous poly(ethyl octadecanedioic acid), anhydrous poly(phenylhexadecanedioic acid), anhydrous penzophenonete-lacarboxylic acid, ethylene glycol bis( Examples include anhydrotrimerite), glycerol tristrimerite-1 anhydride, het acid anhydride, det anhydride, and labromophthalic acid.

A method for producing a curing accelerator made of a modified organic zinc carboxylate includes adding a predetermined amount of an acid anhydride and phenol to an organic zinc carboxylate, preferably in the presence of an inert gas such as nitrogen gas, and at 460 to 200°C. 1-・Kake 70~150℃
and stir for 0.5 to 10 hours. Through such operations, a curing accelerator consisting of a modified organic zinc carboxylate can be easily obtained. In the storage stability test of curing accelerator at 40"C, 3
Even after more than 1 month, no signs of phase separation were observed.
Furthermore, the structure of the curing accelerator made of zinc 9-modified organic carboxylate, which does not show any decrease in curing accelerating function, is not clear, but
Easily soluble in acid anhydrides and epoxy resins, such as zinc octylate, methylhexandrophthalic acid, p-
When denatured using ethylphenol, the phenol zinc ratio shown in formula (C) is 3, the acid anhydride zinc ratio shown in formula (D) is 3, and the mixture is stirred at 100°C for 1 hour in nitrogen gas. , its IR spectrum shows a decrease in the absorption at <3340 cm'' based on the hydroxyl group of phenol and an absorption at <1.790 cm'' based on the acid anhydride group of methylhexandrophthalic anhydride compared to before modification. decrease, appearance of absorption of <1708 crn'' based on free carboxyl groups, <1554 c ml and 1632 c ml based on zinc octylate
Judging from the reversal of absorption intensity of m-', °C1 aa zinc carboxylate, acid anhydride and/or phenol are ゛7
It is presumed that Naretukusunu forms something like an oligomer.

Next, by distributing a curing accelerator made of modified organic zinc carboxylate produced according to the present invention to the acid anhydride,
An acid anhydride curing agent composition can be obtained. As the acid anhydride and L2, one or more of the aforementioned acid anhydrides can be used. The blending method can be carried out at any temperature between room temperature and about 150°C, and the modified organic carboxylic acid zinc and acid anhydride are mixed so that the blending ratio shown in the formula Mix while stirring.

Blending ratio - (T+tJ)/S...(E>(S is the number of moles of the zinc organic carboxylate used for modification, T is the durum of the acid anhydride used in the modified zinc organic carboxylate curing accelerator 4) equivalent number, U is the Durham equivalent number of the acid anhydride added to the modified organic carboxylic acid zinc curing accelerator to produce the curing agent composition) If the blending ratio is 12.5 r or more, the cured product machine If the chemical properties, moisture resistance, etc. are low, 250 or higher, the curing reaction rate of the boxy resin is slow and it is unsuitable.

Furthermore, as another method for obtaining an acid anhydride curing agent composition containing a modified zinc organic carboxylate, when producing the above-mentioned modified zinc organic carboxylate curing accelerator, by using a large amount of an acid anhydride, that is, ( D) According to the method, an acid anhydride curing agent composition can be obtained in the - stage by using the acid anhydride zinc ratio represented by the formula to be about 12.5 to 250. Since the curing agent composition can be obtained by a stepwise operation, it has the advantage that the process is simplified.

When the ratio is less than 12.5 and when it is more than 250, the properties of the cured epoxy resin material deteriorate as in the case described above.

A curing agent composition in which a modified organic zinc carboxylic acid curing accelerator is blended with an acid anhydride, and a curing agent composition produced in one step using a large amount of an acid anhydride both have a function as a curing agent,
The storage stability is good, and in the storage stability test at 40°C, no phenomenon such as phase separation was observed even after 3 months or more.

An epoxy resin composition can be obtained by appropriately mixing an epoxy resin, an acid anhydride curing agent composition obtained by either of the above methods, and other additives. In some cases, epoxy resin, acid anhydride curing agent, modified organic carboxylic acid zinc curing accelerator, and other additives may be added as appropriate.
An epoxy resin composition can also be obtained by mixing at the same time.

The epoxy resin composition thus obtained was heated at 1°O to 17°C.
By heating and curing at a temperature of about 0° C., a cured product with good transparency and no curing unevenness can be obtained. Further, even if this cured product is subjected to a long-term heat aging test at about 125° C., there is very little deterioration in transparency.

Any type of epoxy resin can be used in the present invention as long as it has the desired effects of the present invention. Specifically, bisphenol type epoxy resin obtained from bisphenol A, bisphenol F and shrimp halohydrin, 3,4 epoxycyclohexylmethyl-3
°, alicyclic epoxy resin such as 4゛-epoxycyclohexane carboxylate, novolac type epoxy resin,
Glycidyl ether type epoxy resin such as polypropylene glycol diglycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, Versat
Glycidyl ester-type epoxy resins such as neo-glycidyl esters of carboxylic acids such as IE 5, Versat, and IE 10 (manufactured by Shell Chemical Co., Ltd.), diglycidyl esters of hexahydrophthalic acid and tetrahydrophthalic acid, etc. Illustrated. These can be used in combination of -type or two or more types.

An acid anhydride curing agent composition containing the modified zinc organic carboxylate of the present invention in an epoxy resin, and if necessary, a metal salt of an organic carboxylic acid other than zinc, a metal acetylacetonate, a tertiary amine, imidazole, etc. hardening accelerators, flexibility imparting agents, modifiers, dyes, pigments, bluing agents, inorganic and/or organic fillers such as light diffusing agents, antifoaming agents, coupling agents, antioxidants and reducing agents, etc. The curing accelerator for epoxy resin, epoxy resin curing agent, and epoxy resin composition obtained according to the present invention, which can contain additives such as anti-coloring agents, flame retardants, and mold release agents, can be used for optical purposes, For example, optical lenses, prisms, optical equipment such as transparent flat plates, light emitting elements such as light emitting diodes and encapsulants, optical disk substrates,
Adhesives for light modulation elements and optical fibers, encapsulants for light-receiving elements such as photodiodes and photo1-lansisters, sealing of LSIs and ICs such as ultraviolet erasable El''-ROMs, surfaces of touch panels and solar cells, etc. It can be used as an optical coating material for use in applications, as well as for sealing light-emitting and light-receiving elements such as photocouplers.

Next, the present invention will be explained in detail with reference to Examples.

(Example) Example 1 107 g of zinc 2-ethylhexanoate (trade name: Offtope Zinc, manufactured by Hope Pharmaceutical Co., Ltd.) was placed in a 10100 O four-tube flask equipped with a stirring device, a cooling tube, a nitrogen gas introduction tube, and a thermometer. Methylhexahydrophthalic anhydride (trade name: Rikacid HM-700, manufactured by Shin Nippon Chemical Co., Ltd., hereinafter abbreviated as M e-HHP A) 164 g + (D
) The acid anhydride zinc ratio shown in formula (C) is 3.3+, P-nonylphenol 264g (phenol zinc ratio shown in formula (C) is 4.
) and stirred at 00° C. for 1 hour under nitrogen gas flow, and then cooled to N temperature to obtain a colorless, transparent and uniform modified organic carboxylic acid zinc curing accelerator. 10 parts by weight of the curing accelerator includes 50 parts by weight of Me-HHPA and bisphenol A diglycidyl ether (trade name: Ebicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd., hereinafter abbreviated as DGEBA).
It was easily dissolved in both 100 parts by weight. The curing accelerator was sealed in a glass bottle and stored at 40° C. for 40 days, and its properties were then observed, and it was found to be a colorless, uniform and transparent liquid.

10 parts by weight of the curing accelerator, 1 part by weight of 90 Me-HHPA,
Mix 1 part of DGEBA100 weight and get super! After stirring for 7 minutes for 1 minute, the mixture was degassed under reduced pressure, and the solubility at that time was evaluated. After that, it was cured at a specified temperature for 5 hours to form a 5X20X40
A cured product with a thickness of 400 mm was prepared, and the curing unevenness in appearance was 400 nm.
rn, 800 nm light transmittance measurement (JIS-71
The colorability was evaluated using an ultraviolet-visible spectrophotometer UV-2100 manufactured by Shimadzu Corporation (the same applies hereinafter in the present invention) in accordance with 2005. Cured product at 125℃, 300℃
After heating for a period of time, the light transmittance was measured again.

The results are shown in Table 2.3 In place of 264 g of p-nonylphenol in Example 2,
A colorless, transparent and uniform modified organic carboxylic acid zinc curing accelerator was obtained in the same manner as in Example 1, except that 124 g of p-cresol (phenol zinc ratio represented by formula (C) was 4) was used. 10 parts by weight of the curing accelerator was easily dissolved in either 50 parts by weight of Me-HHPA or 100 parts by weight of DGEBA.

The curing accelerator composition was sealed in a glass bottle and heated at 40°C.
The properties of the product after storage for 40 days were observed, and it was a colorless, uniform, transparent liquid.

Example 3 Instead of 164 g of Me-HHPA in Example 1, Me-
Example 1 except that 328 g of HHPA (the acid anhydride zinc ratio shown in formula (D) was 6.61.396 g (the phenol zinc ratio shown in formula (C) was 6) was used instead of 264 g of p-mononylphenol. In the same manner, a colorless, transparent and uniform modified organic carboxylic acid, zinc curing accelerator was obtained. 0 parts by weight of the curing accelerator was easily dissolved in either 50 parts by weight of Me-HHPA or 1 part by weight of DGEBA. did.

The curing accelerator composition was sealed in a glass bottle and heated at 40°C.
Observe the properties after storage for 40 days.1. However, it was a colorless, uniform and transparent liquid.

Example 4 10.7 g of zinc 2-ethylhexanoate and 16.4 g of Me-HHPA I (D
＞Explain by formula! ! ! Anhydrous zinc ratio is 3°3) and 26.4 g of p-nonylphenol (phenol zinc ratio shown in formula (C) is 4) were added, and the mixture was stirred at 100°C for 1 hour under nitrogen gas flow. A modified organic carvone #i zinc curing accelerator was obtained. This curing accelerator was cooled to 60°C and M e
147.6 g of HHP A (the blending ratio shown in formula (E) was 33.3) was added to obtain a colorless, transparent, and uniform curing agent composition. The curing agent composition 100 heavy slope part is DGEBAiO
It was easily dissolved in 6 parts by weight of O.

The curing agent composition was sealed in a glass bottle and heated at 40°C for 40
The solubility was observed after storage for several days, and it was a colorless, homogeneous and transparent liquid.

Example 5 In the same design as Example 4, M (Sea HHP A 164g
(The acid anhydride zinc ratio, not shown in formula (D), is 333), 10.7 g of 2-ethylhexanoic acid, 26.4 g of P-nonylphenol + the phenol zinc ratio, shown in formula (C), is 4.
) and stirred at 100° C. for 1 hour under nitrogen gas flow, and then cooled to room temperature to obtain a colorless, transparent, and uniform curing agent composition. 100 parts by weight of the curing agent composition is DGEBA1
00 parts by weight.

The curing agent composition was sealed in a glass bottle and heated at 40°C for 40
The solubility was observed after storage for several days, and it was found to be a colorless, homogeneous and transparent liquid. The results are shown in Table 1.

Examples 6 to 13 The same procedure as in Example 5 was carried out except that the type of organic zinc carboxylate, phenol or acid anhydride, zinc phenol ratio, zinc acid anhydride ratio, and stirring temperature were changed. However, when tetrahydrophthalic anhydride (hereinafter abbreviated as THP A) was used as the acid anhydride, the melting point was as high as 102°C, so the solubility test was evaluated at 105°C. Table 1 shows the results.
Shown below.

To Example 14-23 100 parts by weight of the curing agent composition obtained in Examples 1 to 13 and DG
After 1 part by weight of 100 EBA was vigorously stirred for 1 minute, it was degassed under reduced pressure, and the solubility at that time was evaluated. After that, it was cured at a predetermined temperature for 5 hours to create a cured product of 5 x 20
The colorability was evaluated by measuring the light transmittance of nrn. The cured product was heat aged at 125° C. for 300 hours, and the light transmittance was measured again.

However, for the curing agent composition of Example 22 in which THP A was used as the acid anhydride, since it is solid at room temperature, 105
It was mixed with DGEBA at ℃ for 1 minute and evaluated in the same way. The results are shown in Table 2.

Comparative Examples 1 to 3 A curing agent composition was produced in the same manner as in Example 5, except that zinc organic carboxylate was heated in the presence of an acid anhydride. However, only the solubility evaluation of comparative PA4 using THPA,
The temperature was 105°C. The formulation and solubility results are shown in Table 1.

Comparative Example 4 A curing agent composition was produced in the same manner as in Example 5, except that zinc organic carboxylate was heated in the presence of phenols. The formulation and solubility results are shown in Table 1.

Comparative Example 5 A curing agent composition was produced in the same manner as in Example 5, except that the mixture was stirred at room temperature. The formulation and solubility results are shown in Table 1.

Comparative Examples 6 to 9 Using the same equipment as in Example 5, Me-HHPA164
1.0 g of 52-ethyl-4-methylimidazole (hereinafter abbreviated as 2E4MZ) or 1.8-diazabicyclo[5,4,0]undecene-7 (hereinafter DB)
(abbreviated as U) was added and mixed and dissolved at 80℃ for 1 hour.
Parts by weight were mixed at room temperature and cured as described in Examples M14-23 to evaluate transparency. The results are shown in Table 3.

Comparative Example 10 Using the same apparatus as in Example 5, 152 g of THPA was
100 parts by weight of the curing agent obtained by adding DBUl and Og and mixing and dissolving for 21 hours at 110'C and 1 part by weight of 100 parts DGEBA were mixed vigorously at 1.05°C with a WJ of 1 molecule, and after degassing under reduced pressure,
Curing was performed in the same manner as described in Examples 14 to 23, and transparency was evaluated.

The results are shown in Table 3.

Comparative Examples 11 to 5 10 parts by weight of the curing agent composition obtained in Comparative Examples 1 to 5 and DG
100 parts by weight of EBA were mixed at room temperature and cured products were prepared in the same manner as described in Examples 14 to 23, and the solubility, uniformity and transparency of the cured products were evaluated. However, for Comparative Example 14 using THPA, mixing was not carried out at 105°C.
The results are shown in Table 3.

(Effects of the invention) The modified organic carboxylic acid zinc curing accelerator obtained in the present invention easily dissolves in acid anhydrides and epoxy resins, does not cause deterioration such as phase separation even during long-term storage, and The acid anhydride curing agent composition containing the acid zinc curing accelerator does not undergo deterioration such as phase separation even during long-term storage, and can be cured with the acid anhydride curing agent under high temperature and rapid curing conditions of 120°C or higher. The cured epoxy resin is colorless and transparent with no uneven hardening.

Claims (3)

[Claims] (1) Zinc organic carboxylate represented by general formula (A),
Curing acceleration for epoxy resins made of modified organic zinc carboxylate obtained by mixing one or more acid anhydrides and one or more phenols represented by general formula (B) and modifying the mixture by heating. agent. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(A) (R_1 and R_2 are the same or different, phenyl group, C
A nuclear-substituted phenyl group having an alkyl group of _1 to C_1_0, a naphthenic acid residue, a linear or branched alkyl group or alkenyl group of C_1 to C_2_1, a linear or branched C_1 to C_2_1 having a hydroxyl group
) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼... (B) (R_3 is a hydrogen atom or methyl group, C_1 to C_1_6
straight-chain or branched alkyl group, R_4 represents a hydrogen atom or a hydroxyl group, methyl group, methoxy group, ethoxy group, methoxyethyl group, methoxycarbonyl group, methoxycarbonylmethyl group) (2) Zinc organic carboxylate represented by formula (A) in claim 1, one or more acid anhydrides, and one phenol represented by formula (B) in claim 1 Or a curing agent composition for an acid anhydride-based epoxy resin, which contains as an essential component a modified zinc organic carboxylate obtained by mixing two or more kinds and heat-modifying the mixture. (3) Zinc organic carboxylate represented by formula (A) in claim 1, one or more acid anhydrides, and one phenol represented by formula (B) in claim 1 Or an epoxy resin composition containing as an essential component a modified zinc organic carboxylate obtained by mixing two or more kinds and heat-modifying the mixture.